First Steps

A project log for CANtact

The Open Source Car Tool

Eric EvenchickEric Evenchick 03/21/2014 at 20:570 Comments

We need to get this thing working quickly, so the first version will be built out of a dev board, some perfboard, and whatever else is lying around.

For the dev board, I'm planing on using the Tiva C Launchpad, because I have a few of them. Thanks for the free stuff TI! The Tiva C Launchpad hosts a TM4C123GH6PM processor, which has two CAN buses. One of them is shared with the UART which is used for a debug console. We should be able to jumper wires into some test pads to get access to this, and hopefully the debug console will not interfere during normal operation. If it does, we'll be a bit more assertive and cut the traces. 

To actually get on CAN, we'll need transceivers. I want to support one high speed (differential) CAN bus and one low speed (single wire) CAN bus. This means two different transceivers. The MCP2561 is a cheap differential transceiver that's available in a DIP-8. That'll make prototyping easy. As for single wire, the NCV7356 will work. It's available in a SOIC-8, which is only slightly more difficult to mount to a perfboard.

Other than that, everything should be available on the Launchpad, making this a really straightforward hardware build. Time to order some components!